Polymerized cardanol



Patented Apr. 27, 1943 UNITEDSTATES PATENT OFFICE- POLYMERIZED CARDANOLSolomon Caplan, New York, N. Y., assignor to The Harvel Corporation, a.corporation of New Jersey No Drawing.

2 Claims.

Application January 26, 1940. Serial No. 315,760

urushiol, and the phenolic constituent of marking nut shell liquid; andthe present invention relates more particularly to methods and steps forthe polymerization of the above identified materials and products by theuse of monoalkyl acid sulphates and dialkyl sulphates, with the aid ofheat.

The present application is a continuation in part of my copendingapplication Serial Number 291,901, filed August 25, 1939, and throughthat a continuation in part of application Serial Number 109,470, filed.November 6, 1936, patented October 17, 1939, No. 2,176,059. r i

' Reference is hereby made to Patent Number 2,098,824, issued November9, 1937, to M. T. Harvey for a description of cardanol.

The present invention is a departure from the invention described inPatent Number 1,725,793 of M. T. Harvey who uses strong acids such assulphuric acid, among other materials, for the treatment of cashew nutshell liquid; and it is an object of the present invention to obtain aslower polymerizing reaction than is given by strong acids, for thepurposes of facilitating the handling of the material being polymerized,as examples, to allow time to pour large batches from mixing kettlesinto curing pans, also to get the sulphate thoroughly and uniformlydispersed throughout the material to be treated before reaction isinitiated, and without the use of solvents which do not enter into thereaction and which eventually have to be removed.

The present invention is especially advantageous in making polymerizedproducts for electrical insulation in that it eliminates the possibilityof the occlusion of water or unpolymerized material in the polymerizedproduct, such as may occur' when water is used to dilutesulphuric-acidemployed for polymerizing to the solid state.

Also, monoalkyl acid sulphates, dialkyl sulphates, and sulphuric acidcan be used at different steps of the polymerization. For example,sulphuric acid can be used for a. preliminary poly- 1 merization andused in such predetermined quantity as to produce a polymerized productwhich is liquid, after which a monoor di-alkyl sulphate is mixed in andused to bring the treated material to the finally desired state ofpolymerization, such as to an intermediate state or tothe rubbery state.

Also either monoand di-alkyl sulphate can also be used for theprecipitation of metal radicles from cashew nut shell liquid, ashereinafter more fully set forth.

Also, mixtures can be used of any two or of the three sulphate radiclesbearing materials, namely, sulphuric acid, alkyl acid sulphate(monoalkyl acid sulphate) and dialkyl sulphate.

In the case of a mixture of sulphuric acid with either or both themonoalkyl acid sulphate and the dialkyl sulphate, the sulphuric aciddissolves in the alkyl sulphate and the advantage of using a solvent forthe sulphuric acid is obtained together with the advantage gained fromth use of an alkylsulphate.

Other objects and advantages of the present invention will be apparentfrom the foregoing disclosure of illustrative examples of methods,steps, uses and products of the present invention;

The following are givenas examples of phenols which have unsaturatedside chain and whose polymerization can be promoted by material selectedfrom the group consisting of dialkyl sulphates and monoalkyl acidsulphates: the so defined phenols obtained from or derived from juicesof the Anacardium genus of the Ana'- cardiaceae family including cashewnut shell liquid and its phenolic derivatives such as cardol, anacardieacid, Cardanol which is a breakdown derivative of anacardic acid, andother phenolic derivatives of the kind defined obtained some in thedistillate and some in the residue left after distillation, marking nutshell liquid and its phenolic constituents anacardol and the carboxylicphenols, its phenol distillates and phenol distillate residues havingunsaturated side chains;

Japan lac and its phenol constituents and deriva polymerized byconcentrated or fuming sulphuric acid.

As examples of dialkyl and monoalkyl acid sulphates suitable for thepractice of the methods of the present invention the following aregiven: dimethyl sulphate, diethyl sulphate, dibutyl sulphate, dipropylsulphate, diamyl sulphate and the mixed-alkyl sulphates such as ethylbutyl su1-- I phate. butyl amyl sulphate, mono-ethyl acid sulphate,monopropyl acid sulphate, mono-isopropyl acid sulphate and so on.

Illustrative examples of methods of polymerizlng cashew nut shell liquidand other materials according to the present invention are as follows:

ExAmaLE I.Step 1.--To two tons (4000 pounds) of cashew nut shell liquidin a steel tank about one hundred twenty pounds (3% by weight of thecashew nut shell liquid) a commercial grade of mono-isopropyl acidsulphate are added and thoroughly mixed with an agitator and the mixtureheated by means of steam passed through coils of pipe immersed in themixture, the agitator being continued during the heating. The heating iscarried on until the temperature of the mixture reaches 325 E. whichtakes about one and one half hours to two hours in the particularapparatus used for the present example. On reaching the desiredtemperature the steam is turned oil. to discontinue the heating. Duringthis heating the mono-isopropyl acid sulphate reacts with metal bearingcompounds in the cashew nut shell liquid whereby the metals areprecipitated as the sulphat salts. Also, the cashew nut shell liquid isthickened due to the polymerizing action of the mono-isopropyl acidsulphate. On reaching the desired temperature the treated cashew nutshell liquid is drawn from the tank and pumped while still hot through afilter press to remove the precipitated salts, which latter, upon theirprecipitation remain for some time in suspension in the cashew nut shellliquid,

serve as a filter aid in the press and build up a cake through which thecashew nut shell liquid passes. This treated and filtered cashew nutshell liquid, hereinafter called treated cashew nut shell liquid, uponcooling'is liquid and of slightly higher viscosity than commercialuntreated cashew nut shell liquid and is stored in tanks for use and issuitable for making varnishes, resins as by reaction with aldehydes, andfor other uses for which cashew nut shell liquid is known to besuitable, including further polymerization to various stages includingamong others the liquid, semi-liquid and rubbery states in which latterstate the product is known by the trade-mark name of Cardolite.

Step 2.-About ten pounds each of water and concentrated sulphuric acidare mixed with an agitator into one thousand pounds of the above treatedcashew nut shell liquid in a jacketed copper lined kettle and heated bysteam to a temperature of about 320 F. where considerable frothingoccurs, at which point the steam is age or immediate use-as soon as theabove temasiasse pans is placed in ovens and cured for about fifteenhours at about 260 .F. to 275 F.

ExAMrLE II.To a given quantity of the treated cashew nut shell liquid ofStep 1 of Example I there is added about two per cent-by weight ofdiethyl sulphate which is stirred in to get a uniform solution of thetwo. The solution is then heated to bring it up to about 320 F.whereupon the heating is discontinued and the material held untilfrothing caused by evolution of sulphur dioxide gas subsides, whereuponthe material is poured into shallow pans and set in oven to cure for,about fifteen hours at about 260 F. to 275 F. The resulting product isa resilient solid, rubber-like in character, and, like the correspondingmaterial in Step 3 of Example I above, is known on the market asCardolite.

EXAMPLE HI.--The phenolic material of this example is the residueremaining after the distillation of cashew nut shell liquid with steamat about 270 F., and is hereafter in this example called residue.Residue is comprised mostly of phenols having an unsaturated side chainand having a high molecular weight. Into one hundred parts of residuewere dissolved five parts by weight of diethyl sulphate and the solutionheated to about 160 C. where polymerization produced a strong resinousmaterial resistant to high temperature and an insulation of high voltageand frequency currents.

EXAMPLE IV.T0 one hundred parts by weight of Japanese lac (vernisifera)were added five parts by weightof diethyl sulphate which was stirred inand the solution heated up to about 120 C. until the Japanese lac waspolymerized to a ropy consistency when it was set in an oven at about160 C. for about three hours when-it became polymerized and set to atough, hard resin. Metal salts are precipitated from Japanese lac by thesulphate radicles and the precipitate can be removed as by filteringbefore polymerization of the Japanese lac goes beyond the liquid'orfilterable state.

EXAMPLE V.--Into one hundred parts by weight of cashew nut shell liquiddistillation residue, such as is described in Example III, weredissolved about ten parts by weight of diethyl sulphate and the solutionheated for about sixteen hours at about 300 F. The reaction product ishard, horny and tough and has good electrical insulatingcharacteristics.

The reaction product of Example In is rubbery I in comparison with theproduct of Example V.

perature is used. The product when cooled to normal temperature is athick liquid and is suitable for the various uses of cashew nut shellliquid including those above noted for treated cashew nut shell liquid.

Step 3,-A further step for treatment according to the present inventionis to let the material of Step 2 remain inthe kettle and hold until thetemperature rises to 285. F., which rise will occur with the steam offand cold water iiowing through the jacketlat which point about twentypounds of commercial diethyl sulphate ar added and mixed until thetemperature reaches 250 F. when the material is drawn from the kettleand into shallow pans for the depth of about three inches. To get" arubber like consistency, the material called Cardolite, the material inthe shallow Both of these reaction products when produced by heating atabout 300 F. to about 320 F., or in the neighborhood, for about sixteenhours, have reached their ultimate reaction point and will notmaterially change in character when heated longer at these temperatures.

The residue described for Example III and IV can be that obtained by thedistillation of raw cashew nut ,shell liquid or that obtained by thedistillation of cashew nutshell liquid from which naturally occurringmetals have been removed, as for example by the method of Step 1 ofExample I above.

The amount of diethyl sulphate used to polymerize cashew nut she'llliquid residue can be from about 1% to about 10% of the weightot theresidue used and can be varied to suit various needs and conditions towhich the product is to be applied.

- The polymerization products of cashew nut shell liquid distillationresidue of the present invention, as described, and in modificationshave many applications of use for example for electrical insulation, forbrake and clutch and other friction elements facings, for binders forthe abrasive materials of grinding wheels and for binders for otheruses, for coatings and for linings. One way of modifying thepolymerization product of cashew nut shell liquid residue is to condensewith reactive methylene group or similar agents and this condensationcan be carried on simultaneously with the polymerization step or steps.Examples of condensation reagents useful in this manner areformaldehyde, hexamethylene, paraformaldehyde and other polymers offormaldehyde, acetaldehyde and furfuraldehyde and these are describedgenerally as agents which are aldehydes or which contain a reactivemethylene group.

Unlike cashew nut shell liquid, when the aforedescribed methods areemployed cardanol cannot be polymerized to a solid, rubber-like stateand in an ultimate state of polymerization, of being a stable liquid atnormal and elevated temperatures and of having a substantially constantviscosity. At about 25 C. the viscosity of this ultimate liquid polymeris about 25 seconds as measured with an-Armour pipette. And this liquid,ultimate polymer can be subjected to higher temperature withoutappreciably thickening 01' in Also, polymerized car-' creasing inviscosity. danol dififers from polymerized cashew nut shell liquid inseveral respects which are important in the technical applications andcommercial uses of this product. For example, the polymerized cardanolreacts with hexamethylene tetramine to produce an ultimate condensationreaction product which is a flexible resin that does not have anyelasticity whereas polymerized cashew nut shell liquid reacts withhexamethylene .etramine to form an ultimate condensation reactionproduct which is a rubber-like resin which has an appreciable degree ofelasticity. polymerized cardanoP' when mixed with an anhydroformaldehydealkylamine (butyl or amyl,

for example) remains inactive at the lower temperature and up to about100. F. for an indefinite time whereas polymerized cashew nut shellliquid reacts with an anhydroformaldehyde alkylamine at normaltemperature to form a condensation reaction product, The polymerizedcardanoP' can be condensed with an anhydroformaldehyde alkylamine byraising the temperature above about 100 F., for example, to about 200 F.to obtain a condensation reaction product. This inactivity of thepolymerized cardanoP permits its use in large quantities when mixed withan anhydroformaldehyde alkylamine when the mixture is applied inincrements and set in increments by the raising of the temperature ofthe applied increment. I

Polymerized cardanol at the several stages of polymerization up to theultimate stage of polymerization can be milled with rubber to suitvarious purposes, and, when desired, can be set or condensed with analdehyde or similar material, after being mixed with the rubber. Also,cardanol or partly polymerized cardanol can be mixed with a polymerizingagent such as diethyl sulphate and a condensing agent such asfurfuraldehyde and then heated to promote condensation simultaneouslywith the polymerization or further or ultimate polymerization to producedesirable products.

Having thus described my. invention, what I claim and desire to protectby Letters Patent is:

1. A liquid polymer of cardanol, obtained by heating cardanol in contactwith a dialkyl sulphate, which liquid polymer has the characteristics(1) of being reactive with aldehydes and reactive methylene groupcontaining agents to form condensation products (2) of being furtherpolymerizable from intermediate states of polymerization to an ultimatestate of polymerization in which it is liquid, and (3) in an ultimatestate of polymerization, of being a stable liquid at normal and elevatedtemperatures and of having a substantially constant viscosity.

2. Polymerized cardanol in a liquid, stable and ultimate polymerizationstate obtained by heating cardanol in contact with a dialkyl sulphate.

SOLOMON CAPLAN.

